1. Technical Field
This invention relates generally to systems for tracking, analyzing, and evaluating athletic performance in team sports and displaying the evaluation results and more specifically to evaluating the performance of multiple football players during actual competition.
2. Background
The performance of an individual athlete can be scientifically evaluated by analyzing the motion of the athlete in response to a defined stimulus. Given a particular stimulus, an athlete""s responsive change of position over time can be measured by a tracking system. These measurements are useful for evaluating the performance of an athlete. Current systems derive velocity, acceleration, and response time from tracking system data. Some current systems use a computer-generated xe2x80x9cvirtual opponentxe2x80x9d shown on a screen in a controlled manner to provide the stimulus. This allows precise knowledge of the timing and dynamics of the stimuli. After the stimulus is presented, the athlete""s motion is tracked to measure the response.
A variety of tracking systems are currently available. Target tracking methods span spectrums between purely active tracking and purely passive tracking and between cooperative and uncooperative targets. The term xe2x80x9ctargetxe2x80x9d as defined and used herein refers to the person or thing sought to be tracked. For example, an athlete is a xe2x80x9ctargetxe2x80x9d for tracking purposes. Purely active tracking sends a signal into the space potentially containing a target and receives a return of the signal reflected by the target which is analyzed to determine target location. Radar of the World War II era is an example of purely active tracking. Purely passive methods rely on the target emitting a signal which a sensor can discriminate from the background. Infrared optical trackers may be purely passive trackers. A cooperative target is one that assists the tracker. For example, attachment of a corner reflector or an infrared beacon to the target would help, respectively, radars and infrared optical sensors to track the target.
For several purposes, it is desirable to track an athlete. The data relating to the motion of an athlete over time has been found useful in sports testing and training. Current known systems track a single athlete. U.S. Pat. No. 6,308,565 to French, et al., (Oct. 30, 2001) discloses a testing and training system that tracks a single athlete to evaluate his performance. French further discloses the use of commercially available tracking systems using optical sensors. French also discloses a game system xe2x80x9cfor determining changes in an overall physical location of the respective player in a respective defined physical space,xe2x80x9d which tracks physical movement of a player in a different (xe2x80x9crespectivexe2x80x9d) space and then puts the sum of all actions together in a virtual reality game. U.S. Pat. No. 6,148,262 to Fry (Nov. 14, 2000) discloses a performance tracking device using Global Positioning System (GPS) data in a personal computer that moves with the athlete for jogging, bicycling, and the like. U.S. Pat. No. 6,013,007 to Root, et al. (Jan. 11, 2000) discloses a personal athletic performance monitor that uses GPS data and is carried by the athlete. The athlete can later download the data into a computer for analysis. U.S. Pat. No. 5,812,049 to Uzi (Sep. 22, 1998) discloses a system for measuring the lap time of a swimmer at swimming meets, the system comprising a plurality of tracking systems each deployed in a lane. U.S. Pat. No. 5,825,327 to Krasner discloses garments containing GPS receivers. The focus of current systems is on individual athletic performance.
The methods known in the art do not meet all needs. Current systems are inadequate to evaluate how an athlete""s performance varies depending on his head-to-head competitors and the athlete""s own team members with whom he interacts directly during competition. For example, the performance of an offensive right guard on a football team may vary depending on who is playing offensive center and who is playing offensive right tackle because the actions of neighboring linemen must be coordinated to be effective. Likewise, the performance of the athlete who is playing defense opposite the offensive linemen of interest will affect the performance of the offensive linemen. Coaches, commentators, and fans would like to know what combination of players is the best match for a given combination of competitors. Current systems do not answer this question. Coaches must rely on experience and direct observation to analyze performance. The resulting analysis is necessarily highly subjective. The need for a way to objectively analyze player performance in competition is unmet.
Another unmet need is the need to visualize the dynamics of players in an actual, as opposed to simulated, competition. While video images of players in motion do provide a lot of information, it is desirable to enhance that information with actual dynamic measurements. While such measurements can currently be obtained in simulated laboratory settings, current systems are not readily adaptable to making dynamic measurements of athletes in actual competition. For example, the invention of French, supra, uses optical sensors tracking one athlete in a xe2x80x9crespective spacexe2x80x9d containing only one athlete. French""s system does not track a plurality of athletes in the same space, as is required for tracking during team competition. The optical sensors cannot keep the target in view when other player""s interpose themselves between the sensor and the target.
Accordingly, the present invention provides a method and apparatus for tracking athlete""s during team competition, analyzing the performance of the athletes, and displaying digital video images of the athletes along with selected measured and derived data about the motion of the athletes. In one embodiment, graphical icons representing movement parameters are superimposed upon the video images of a plurality of athletes during athletic play. In another embodiment, the motion data of a particular athlete are analyzed for a plurality of playing environments, including teammates and opponents, to determine the conditions under which the particular athlete excels or fails. In yet another embodiment, combinations of moving picture images of athletes and athlete motion data are provided to sports commentators for display to television audiences. In a particular embodiment, the images and data are provided to sports fans at remote locations.